We are sure one day the air in Beijing will be much ______ than today.
| A．clean | B．cleaner |
| C．cleanest | D．the cleanest |
--Would you like to do ______ to protect our earth? -- Of course, I’d love to.
A.anything useful
B. useful something
C. something useful
—The dictionary is a useful _______ for understanding new words.
—I think so.
A. secret B. tool C. way
My mother asked me _______.
A.what I was doing
B. what are you doing
C.what was I doing
Linda hasn’t finished her homework ______.
A. already B. just C. yet
The population now is much ______ than that 20 years ago.
A. large B. larger C. largest